diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 3a221d8fc..1494d8dd9 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -5,11 +5,15 @@
 ---
 version: 2
 
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.8"
+
 sphinx:
   configuration: docs/source/conf.py
 
 python:
-  version: "3.8"
   install:
     - requirements: requirements_docs.txt
     - requirements: requirements.txt